That 300mm is a different measurement. It's not a typo and they're refering to the size of the wafers, in this case 300mm diameter (very close to 12 inches).
Yes. In addition, wafer size is another important metric of fab capabilities aside from process node, since it roughly translates into production rate.
This is coming in late, but the short answer is "I have no idea".
The slightly longer answer is "I don't know. But once you have the space and equipment and you're sure you can handle everything safely you still need to staff this and build up some institutional knowledge." If you're thinking this far, you should ask why 65nm? Because it's a process node you know a certain microprocessor was built on? It's just a benchmark that's useful for working out your sense of what it costs to do these from scratch?
The cheapest way to get the equipment would be buying out a fab that's shutting down. When I was in undergrad, I got to play in a 5 micron (5000nm) fab on campus because the previous owner of all the equipment gifted it to the university instead of scrapping it. My gut sense is that there's nothing at 65nm that's unprofitable yet, so you're not getting cheap stuff.
(a 6 micron node was commercialized in 1974, this university lab was opened in 1993. 65nm was commercialized in 2005. While Moore's Law held, more or less, through much of 1974-2005, I think we can say that the difficulties and necessary capital investments increased super-linearly over that time. And 20 year old manufacturing tech seems much more useful now than it did in '93. The STM32 family of microcontrollers, a very strong line, is spread over the 132-40nm range of process nodes.)
